Equus roundworms (Parascaris univalens) are undergoing rapid divergence due to host and environment factors

Abstract Background The evolution of parasites is often directly affected by the host's environment. Studies on the evolution of the same parasites in different hosts are extremely attractive and highly relevant to our understanding of divergence and speciation. Methods Here we performed whole genome sequencing of Parascaris univalens from different Equus hosts (horses, zebras and donkeys). Phylogenetic and selection analysis was performed to study the divergence and adaptability of P. univalens. Results At the genetic level, multiple lines of evidence support that P. univalens were mainly separated into two clades (Horse-derived and Zebra & Donkey-derived). This divergence began at 300-1000 years ago, and we found that most of the key enzymes related to glycolysis were under strong positive selection in zebra & donkey-derived roundworms, but lipid related metabolism system was under positive selection in the horse-derived roundworms, indicating that the adaptive evolution of metabolism may drive the divergence in past few centuries. In addition, we found that some drug-related genes have a significantly higher degree of selection in different populations. Conclusions This work reports evidence that the host’s diet drives the divergence of roundworms for the first time, and also supports that divergence is a continuous and dynamic process, and continuous monitoring of the effects of differences in nutritional and drug history on rapid evolution of roundworms are conducive to further understanding host-parasite interactions.

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Identification of an ancient endogenous retrovirus, predating the divergence of the placental mammals

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2012.0503 ◽

2013 ◽

Vol 368 (1626) ◽

pp. 20120503 ◽

Cited By ~ 29

Author(s):

Adam Lee ◽

Alison Nolan ◽

Jason Watson ◽

Michael Tristem

Keyword(s):

Rapid Evolution ◽

Endogenous Retrovirus ◽

Arms Race ◽

Endogenous Retroviruses ◽

Selfish Genetic Elements ◽

Host Parasite Interactions ◽

Combined Use ◽

Minimum Age ◽

Host Parasite ◽

First Time

The evolutionary arms race between mammals and retroviruses has long been recognized as one of the oldest host–parasite interactions. Rapid evolution rates in exogenous retroviruses have often made accurate viral age estimations highly problematic. Endogenous retroviruses (ERVs), however, integrate into the germline of their hosts, and are subjected to their evolutionary rates. This study describes, for the first time, a retroviral orthologue predating the divergence of placental mammals, giving it a minimum age of 104–110 Myr. Simultaneously, other orthologous selfish genetic elements (SGEs), inserted into the ERV sequence, provide evidence for the oldest individual mammalian-wide interspersed repeat and medium-reiteration frequency interspersed repeat mammalian repeats, with the same minimum age. The combined use of shared SGEs and reconstruction of viral orthologies defines new limits and increases maximum ‘lookback’ times, with subsequent implications for the field of paleovirology.

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Disentangling non-specific and specific transgenerational immune priming components in host–parasite interactions

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2019.2386 ◽

2020 ◽

Vol 287 (1920) ◽

pp. 20192386

Author(s):

Frida Ben-Ami ◽

Christian Orlic ◽

Roland R. Regoes

Keyword(s):

Genetic Epidemiology ◽

Ecological Systems ◽

High Dose ◽

Immune Priming ◽

Specific Effects ◽

Host Parasite Interactions ◽

Pasteuria Ramosa ◽

Different Strains ◽

Host Parasite ◽

First Time

Exposure to a pathogen primes many organisms to respond faster or more efficiently to subsequent exposures. Such priming can be non-specific or specific, and has been found to extend across generations. Disentangling and quantifying specific and non-specific effects is essential for understanding the genetic epidemiology of a system. By combining a large infection experiment and mathematical modelling, we disentangle different transgenerational effects in the crustacean model Daphnia magna exposed to different strains of the bacterial parasite Pasteuria ramosa . In the experiment, we exposed hosts to a high dose of one of three parasite strains, and subsequently challenged their offspring with multiple doses of the same (homologous) or a different (heterologous) strain. We find that exposure of Daphnia to Pasteuria decreases the susceptibility of their offspring by approximately 50%. This transgenerational protection is not larger for homologous than for heterologous parasite challenges. Methodologically, our work represents an important contribution not only to the analysis of immune priming in ecological systems but also to the experimental assessment of vaccines. We present, for the first time, an inference framework to investigate specific and non-specific effects of immune priming on the susceptibility distribution of hosts—effects that are central to understanding immunity and the effect of vaccines.

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Disentangling unspecific and specific transgenerational immune priming components in host-parasite interactions

10.1101/429498 ◽

2018 ◽

Cited By ~ 1

Author(s):

Frida Ben-Ami ◽

Christian Orlic ◽

Roland R. Regoes

Keyword(s):

Bacterial Pathogen ◽

Immune Memory ◽

High Dose ◽

Immune Priming ◽

Host Parasite Interactions ◽

Pasteuria Ramosa ◽

Wide Range ◽

Different Strains ◽

Host Parasite ◽

First Time

AbstractExposure to a pathogen primes many organisms to respond faster or more efficiently to subsequent exposures. Such priming can be unspecific or specific, and has been found to extend across generations. Disentangling and quantifying specific and unspecific effects is essential for understanding the genetic epidemiology of a system. By combining a large infection experiment and mathematical modeling, we disentangle different transgenerational effects in the crustacean model Daphnia magna exposed to different strains of the bacterial parasite Pasteuria ramosa. In the experiments, we exposed hosts to a high-dose of one of three parasite strains, and subsequently challenged their offspring with multiple doses of the same or a different strain, i. e. homologously or heterogously. We find that exposure to Pasteuria decreases the susceptibility of a host’s offspring by approximately 50%. This transgenerational protection is not larger for homologous than for heterologous parasite challenges. Our work represents an important contribution not only to the analysis of immune priming in ecological systems, but also to the experimental assessment of vaccines. We present for the first time an inference framework to investigate specific and unspecific effects of immune priming on the susceptibility distribution of hosts — effects that are central to understanding immunity and the effect of vaccines.Author summaryImmune memory is a feature of immune systems that forms the basis of vaccination. In opposition to textbook accounts, the ability to specifically remember previous exposures has been found to extend to invertebrates and shown to be able to be passed on from mother to off-spring, i. e. to be transgenerational. In this paper, we investigate the extent of this specificity in unprecedented detail in water fleas. We exposed water flea mothers to different strains of a bacterial pathogen and challenged their offspring with a wide range of doses of a strain that were either identical to (homologous) or different from (heterologous) the strain, to which the mother had been exposed. We find that, while exposure of the mother reduces the susceptibility of the offspring, this effect is not specific. This work outlines the limits of specific transgenerational immune memory in this invertebrate system.

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Louse (Insecta: Phthiraptera) infestations of the Amur Falcon (Falco amurensis) and the Red-footed Falcon

Ornis Hungarica ◽

10.1515/orhu-2015-0005 ◽

2015 ◽

Vol 23 (1) ◽

pp. 58-65 ◽

Cited By ~ 3

Author(s):

Imre Sándor Piross ◽

Péter Fehérvári ◽

Zoltán Vas ◽

Szabolcs Solt ◽

Éva Horváth ◽

...

Keyword(s):

South Africa ◽

Life History ◽

Host Species ◽

Life History Traits ◽

Population Parameters ◽

Model Species ◽

Host Parasite Interactions ◽

Louse Species ◽

Host Parasite ◽

First Time

Abstract Little is known about the louse species harboured by Red-footed and Amur Falcons despite the fact that various life-history traits of these hosts make them good model species to study host-parasite interactions. We collected lice samples from fully grown Amur (n=20) and Red-footed Falcons (n=59), and from nestlings of Red-footed Falcons (n=179) in four countries: Hungary, India, Italy and South Africa. We identified 3 louse species on both host species, namely Degeeriella rufa, Colpocephalum subzerafae and Laembothrion tinnunculi. The latter species has never been found on these hosts. Comparing population parameters of lice between hosts we found significantly higher prevalence levels of D. rufa and C. subzerafae on Amur Falcons. Adult Red-footed Falcons had higher D. rufa prevalence compared to C. subzerafae. For the first time we also show inter-annual shift in prevalence and intensity levels of these species on Red-footed Falcons; in 2012 on adult hosts C. subzerafae had higher intensity levels than D. rufa, however in 2014 D. rufa had significantly higher intensity compared to C. subzerafae. In case of nestlings both louse species had significantly higher preva lence levels than in 2014. The exact causes of such inter-annual shifts are yet to be understood.

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Host–parasite fluctuating selection in the absence of specificity

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2017.1615 ◽

2017 ◽

Vol 284 (1866) ◽

pp. 20171615 ◽

Cited By ~ 14

Author(s):

Alex Best ◽

Ben Ashby ◽

Andy White ◽

Roger Bowers ◽

Angus Buckling ◽

...

Keyword(s):

Life History ◽

Fluctuating Selection ◽

Specific Host ◽

Host Parasite Interactions ◽

Stochastic Fluctuations ◽

Selection Dynamics ◽

Ecological Feedbacks ◽

Host Life ◽

Host Parasite ◽

First Time

Fluctuating selection driven by coevolution between hosts and parasites is important for the generation of host and parasite diversity across space and time. Theory has focused primarily on infection genetics, with highly specific ‘matching-allele’ frameworks more likely to generate fluctuating selection dynamics (FSD) than ‘gene-for-gene’ (generalist–specialist) frameworks. However, the environment, ecological feedbacks and life-history characteristics may all play a role in determining when FSD occurs. Here, we develop eco-evolutionary models with explicit ecological dynamics to explore the ecological, epidemiological and host life-history drivers of FSD. Our key result is to demonstrate for the first time, to our knowledge, that specificity between hosts and parasites is not required to generate FSD. Furthermore, highly specific host–parasite interactions produce unstable, less robust stochastic fluctuations in contrast to interactions that lack specificity altogether or those that vary from generalist to specialist, which produce predictable limit cycles. Given the ubiquity of ecological feedbacks and the variation in the nature of specificity in host–parasite interactions, our work emphasizes the underestimated potential for host–parasite coevolution to generate fluctuating selection.

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Not so sterile after all: The endomicrobiome of plerocercoids of the cestode parasiteSchistocephalus solidusand changes to the microbiome of its Threespine Stickleback host

10.1101/290015 ◽

2018 ◽

Author(s):

Megan Hahn ◽

Nolwenn Dheilly

Keyword(s):

Horizontal Transmission ◽

Body Cavity ◽

The Body ◽

Schistocephalus Solidus ◽

Host Parasite Interactions ◽

Host Parasite ◽

First Time ◽

Host Tissues

AbstractDespite the growing recognition of the role of bacteria in animal biology, the microbiome of parasites remains largely unexplored. In particular, the presence of bacteria in tapeworms has never been investigated and parasites that exit the intestine would be considered sterile. We characterized for the first time the microbiome of a tapeworm.Schistocephalus solidusplerocercoids, collected from the body cavity of its stickleback host, were found to harbor a complex microbiome. The most abundant and the most prevalent bacteria wasPolynucleobacter sp.. In addition,S. solidusinfection was associated significant changes in the stickleback host gut microbiome with an increase in microbial load and changes in diversity and composition. Finally, the same bacteria were often found inS. solidusand the stomach and intestine of the corresponding hosts, a result that highlights the importance of characterizing the microbiome of host tissues and parasites from the same individuals to assess the potential for horizontal transmission of microbes. This study clearly emphasizes the need for further characterization of the microbiome of a broad range of parasites and for studies to determine the ecological, evolutionary and functional role that microbes play in host-parasite interactions.

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Panstrongylus diasi Pinto & Lent, 1946 (Hemiptera, Reduviidae, Triatominae): first record in Mato Grosso, Brazil

Check List ◽

10.15560/15.2.259 ◽

2018 ◽

Vol 15 (2) ◽

pp. 259-264

Author(s):

Mirian Francisca Martins ◽

Sinara Cristina de Moraes ◽

Marcos Takashi Obara ◽

Cleber Galvão

Keyword(s):

Trypanosoma Cruzi ◽

Urban Area ◽

Chagas Disease ◽

New Record ◽

First Record ◽

Mato Grosso ◽

Host Parasite Interactions ◽

Host Parasite ◽

First Time

Panstrongylus diasi Pinto & Lent, 1946, previously known from throught the Brazilian center-west, is reported for the first time in Mato Grosso state, Brazil. We found 3 specimens, 1 of them from an urban area of Barra do Garças. The new record of P. diasi is important for the understanding of the epidemiology of Chagas disease, mainly because this species is found naturally infected with Trypanosoma cruzi (Chagas, 1909). Studies on the ecology, biogeography, and vector–host/parasite interactions of P. diasi are essential.

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Identification of transcripts relating to host-parasite interactions and feeding-associated activities through de novo transcriptome sequencing of branchiuran fish lice, Argulus foliaceus (Linnaeus, 1758) and Argulus coregoni Thorell, 1865

10.21203/rs.3.rs-285509/v1 ◽

2021 ◽

Author(s):

Aisha AmbuAli ◽

John B. Taggart ◽

Michael Bekaert ◽

Stefanie Wehner ◽

Sean J. Monaghan ◽

...

Keyword(s):

High Throughput Sequencing ◽

De Novo ◽

Gene Clusters ◽

Data Set ◽

Immune Mediators ◽

Host Parasite Interactions ◽

Argulus Foliaceus ◽

Argulus Coregoni ◽

Host Parasite ◽

First Time

Abstract BackgroundThe genus Argulus, whose members are widely known as “fish lice”, comprises a group of obligate ectoparasites that cause argulosis. This parasitic disease affects both wild and cultured fish populations and can lead to significant mortalities. Our previous work confirmed the presence of immunomodulatory or other active products in the secretions of Argulus foliaceus (Linnaeus, 1758) using proteomic analysis conducted on secretory / excretory products (SEPs). Some of the compounds identified have also been described for other host-associated Crustacea, particularly the parasitic copepod Lepeophtheirus salmonis (Krøyer, 1837). The identification and characterisation of such components can contribute to the understanding of the host-parasite relationship for argulids and may also assist in the development of novel control methods, however, due to limitations in existing genomic resources, only 27 proteins could be confirmed in SEPs. In this study, high-throughput sequencing, supported by the use of a range of bioinformatics tools and methodologies were employed on host-associated stages of A. foliaceus and A. coregoni Thorell, 1865 to explore elements of the transcriptome associated with host-parasite interactions and feeding-associated activities.ResultsThe transcriptome data produced in the current study comprises the largest current genomic data set for the genus Argulus, with 84,256,934 reads, assembled into 66,940 contigs for Argulus foliaceus, and 10,840,092 reads, assembled to give 40,954 contigs, representing the first transcript sequences for Argulus coregoni. A pre-existing transcriptome dataset for A. siamensis was also analysed. An overview of the functional roles of the transcripts and their respective proteins for the three Argulus species was performed using GO analysis. A phylogenetic tree was also constructed, using the top 100 shared genes for the four transcriptome datasets available for Argulus. From this analysis, A. coregoni was revealed to be more closely related to A. foliaceus than to A. siamensis. The application of OrthoVenn software to the Argulus spp. transcriptome datasets identified 6,674 shared gene clusters. The transcriptomic analysis in this study, supported by earlier proteome work, has contributed to identifying, for the first time, a range of proteins / genes in Argulus, and more widely for the Branchiura, that have been previously characterised as being important immune mediators for other aquatic and terrestrial blood-feeding arthropods. Data are available via EBI with the project number PRJEB34947.Conclusions In addition to confirming the presence of a range of key immune mediators in Argulus spp. for the first time, this study has provided important genomic tools for researchers seeking to better understand the biology and host interactions of Argulus spp. The created resources unlock the possibility of characterising protein targets relating to host-parasite interactions and feeding-associated activities and can thereby assist the future development of vaccines, veterinary drugs, functional feeds and other tools that might contribute to improved integrated pest management of these globally important parasites.

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